Gazing down on the spectacular view from a mountaintop can take your breath away. That breathlessness is oftentimes more than just an awestruck reaction to the sights. It can be a symptom of altitude sickness, an illness that can strike hikers, mountain climbers, skiers and anyone who hits the 8,000-foot mark on a mountain.

Antibiotics have been called "wonder drugs," because of their ability to treat bacterial infections that were once deadly. Antibiotics have saved countless lives since they were first introduced 60 years ago. But over use of these drugs has allowed some bacteria to become resistant to them.

The human appendix is a 3- to 6-inch narrow tube located where the small and large intestines join. It's mostly known for becoming inflamed, affecting thousands of Americans each year. To learn more about the appendix, take this quiz.

Each year, more than a million Americans die of heart attacks and other forms of heart disease. Low-dose aspirin therapy is one weapon in the arsenal against heart disease that also includes healthy dieting, adequate exercise, and not smoking. Learn more about aspirin's role in combating heart disease by taking this quiz

The itching caused by athlete's foot can be intense. Named for the active people who seem most prone to this condition, athlete's foot can affect even couch potatoes. Find out more by taking this multiple-choice quiz.

Autism is a developmental disability that usually starts in early childhood. Because different children can have widely different symptoms, autism is classified as a "spectrum disorder," which means it is a group of disorders with similar features.